Recently, there has been an increased interest in a new type of laser device called a vertical cavity surface emitting laser (VCSEL). Several advantages of VCSEL devices are apparent, such as having a circular beam, two-dimensional array capability, and allowing wafer scale testing. These advantages are due in part from advances in metal organic vapor phase epitaxy (MOVPE) and molecular beam epitaxy (MBE) that allow monolithic growth of diffractive Bragg reflectors (DBRs) for VCSELs.
However, even with these advantages, VCSEL devices are more susceptible to electro-static discharge (ESD) events because of smaller active volume. Electro-static discharge events are events where a high static charge is built up and subsequently discharged. When the high static charge discharges through a VCSEL, it will be catastrophically damaged. Thus, conventional VCSEL's are limited to applications that are not susceptible to ESD events, which reduces the number of possible applications for VCSEL's.
Thus it is highly desirable and an object of the present invention to provide a protective circuitry to increase the VCSEL ESD damage threshold.
It is another purpose of the present invention to provide for a method to integrate the protective diode with the VCSELs.